EGLIN AFB — The Marine variant of the F-35 fighter jet has been grounded after a flight at the base experienced an engine problem during takeoff.

Flights of the plane have been banned across the country until the problem is addressed.

On Jan. 16 as a pilot was starting his takeoff, a failure of one of the fueldraulic lines on the side of the motor was noticed, said Lt. Col. David Berke, commander of Marine Fighter Attack Training Squadron 501 at Eglin.

The pilot was moving at a relatively slow speed and was able to stop the jet with no additional problems. No one was injured and the plane was not damaged, Berke said.

The Marine model of the plane, the F-35B, is designed for short takeoff and vertical landing capability, but was performing a traditional takeoff when the flight was aborted.

It was the first time a $70 million-plus F-35B had to stop a flight during takeoff at Eglin.

“We rarely fly aircraft where we have issues that arise during flight,” Berke said.

Aircraft maintainers evaluated the cause of the failure and reported their findings to the command staff. The planes were grounded program-wide Jan. 18.

Engineers are continuing to investigate the root cause of the problem, which may be a manufacturing defect in the fueldraulic lines.

“Once they come up with a solution, we will start flying airplanes again,” Berke said.

The incident marks the longest grounding for any variant of the F-35. The jets have been grounded four times previously, but not for more than 15 days and not once since they started flying at Eglin last year.

Berke said it is not uncommon for new aircraft to have problems in their first years.

“This is not unique to the F-35B,” he said. “With immature systems these discoveries can and will present themselves over time.”

He doesn’t expect the grounding to slow down plans to train pilots and maintainers this year.

He said there is plenty of work to do improving and expanding the training curriculum, maintaining the jets and using state-of-the-art flight simulators.